Sigma-delta modulators (SDM) are used in many different areas of technology. They have become particularly important in the analog/digital and digital/analog conversion of electrical signals. Another typical area in which SDMs are used is in phase feedback loops, so-called PLLs (phase-locked loop), in which SDMs are used, for example, as phase frequency detectors (PFD) or to generate a high-resolution fractional modulation signal.
As the speed of integrated circuits increases, SDMs are becoming interesting for radio-frequency applications. “Fast” SDMs with short internal signal propagation times are needed for radio-frequency applications.